presentazione Capannelli 21 10 2016.ppt [modalità ... · Nella distillazione a membrana il ruolo...

Membrane Technologies

Membrane

Selective compact support (≈1 µm)

Macroporous support (≈100 µm)

MEMBRANE DEFINITION

A membrane permits passage of certain

components and retains certain other

components of a mixture

A membrane is a barrier that

allows restricted and/or

regulated passage of one or

more species through it

MEMBRANE APPLICATION

Membranes can be used for different purposes:

- separation and/or concentration (RO, NF, UF, MF, ED, D, PV, etc.).

- control and optimization of the mass transfer for a multiphase system

“membrane contactor” (MD, Saturators, Diffuser, etc.).

- control and optimization of a chemical reaction, where the chemical

reaction is a an integrated membrane process (eg. separation and/or

contactor processes) CMR.

Distillazione a membrana

La soluzione concentrata viene posta a contatto con una

membrana porosa e (idrofobica) che consente il passaggio

attraverso pori del vapor d’acqua ma non quello dell’acqua

liquida e delle sostanze in essa disciolte.

Il passaggio del vapore viene velocizzato applicando il

vuoto.

Il vapore viene poi condensato esternamente al modulo

dove è alloggiata la membrana.

Immagine della superficie di una membrana tipo GORE-TEX

usata per le prove di distillazione

Nella distillazione a membrana il ruolo della pressione osmotica non è rilevante

Si possono così trattare soluzioni altamente concentrate dove l’osmosi inversa non può

essere applicata

Membrane classification

composite

dense porous

symmetric

asymmetric

skinned

Separation mechanism

Porous membranes act as a sieve only allowing the passage of particles whose dimension is smaller than the pore dimension.They are used, for example, in MF, UF, D.

Dense membranes (non porous) separate the species according to their different solubility and diffusion through the dense membrane layer. Their application is, for example, in RO and NF.

Membrane Structure

Dense Layer Retentate

(Solute)Macroporous sub-layer

Substrate Layer

Permeate

(Solvent)

Nomenclature

Feed

Retentate

or

Concentrate

Permeate

or

Filtrate

PRESSURE-DRIVEN MEMBRANE PROCESSES

Microfiltration is mainly used as a clarification

technique, separating suspended particles from

dissolved substances, provided the particles meet

the size requirements.

Ultrafiltration is a method to purify, concentrate,

and fraction simultaneously macromolecules or

fine colloidal suspensions.

Reverse osmosis is essentially considered as a

dewatering technique.

Nanofiltration is a relatively new process,

employing charged membranes having larger

pores than RO ones, but too small to allow the

permeation of many organic compounds, such as

sugars.

Osmosis...Reverse Osmosis

Osmosis

WaterSolution

WaterSolution

P

Reverse

Osmosis

Osmotic

Equilibrium

Solution Water

Osmotic

Pressure


Example of

components

separated by

pressure-

driven

membrane

processes

Microfiltration

�Separates on the basis of size

�Characterised on basis of pore diameter

�Polarisation can occur, and reduce cutoff

�Sometimes a smaller pore size gives better

results

Ultrafiltration

� This fractionates on the basis of molecular size

� The resistance to flow through the membrane is

hydraulic

� The membrane is generally considered to be truly

porous

Nanofiltration

� Characterised on passage of given solutes e.g.

Lactose

Sodium chloride

Magnesium Sulphate

� Rejects inorganics on basis of charge

� Rejection a function of:

valency

charge density

ionic mix

� Negative rejections of some ions possible

Reverse Osmosis

�Non-porous membrane

�Characterised by retention of Sodium

Chloride


Since ultrafiltration deals with the

separation of fairly large molecules, the

employed pressures are fairly low (< 5-

10 bar).

In contrast, pressures involved in

reverse osmosis are fairly high (35-100

bar), in order to overcome the high

osmotic pressures of the small solutes.

Nanofiltration needs lower operating

pressures (10-30 bar), compared to RO.

RO

NF

UF

MF

PRESSURE (DRIVING FORCE) POROSITY

35-100 Bar

10-30 Bar

< 5-10 Bar

1-4 Bar


Unlike conventional filtration processes which operate in a "dead-

end" mode, membranes are configured to be operated in the "cross-

flow" mode, where feed is pumped over the membrane surface,

resulting in two product streams (permeate and retentate).

Properties

� Operating Environment

– pressure

– temperature

– pH

– solvents

– oxidants

– foulants

� Surface Chemistry

– hydrophobic/phillic

– chemical interactions

Specifying an Effective

Membrane ProcessFeed

Volume

Physical properties- viscosity

- temperature

- suspended solids

Chemical properties

- analysis

- pH

- dissolved solids

- chemical compatibility

Retentate

- ‘Product’?

- ‘Waste Concentrate’?

- Required specification?

Permeate

- ‘Product’? Pure fluid?

- Recycle water?

- ‘Waste’?

- Required specification?

Operating constraints ?e.g.. processing temperature

residence time

cleaning chemical disposal

Operating conditions

Low energy consumption

High accumulation velocity

Quick flux decrease

Lower accumulation

Slower flux decrease

High energy consumption for

recirculation

Qfeed= Qpermeate + Qretentate

Qfeed= Qpermeate + Qdischarge

Dead-end

Cross-flow

Pilot Plant Trials

– Pilot Trial WorkTrial Information

� Flux as a function of concentration

� Retention as a function of concentration

� Degree of fouling

� Effectiveness of cleaning

� Membrane Life

� Pressure drop as a function of concentration

� Quality of product

� Power consumption

Pilot plant >>>

Full Scale Operation

�Factors Influencing the Design of a Full

Scale Plant

�Membrane Configuration

�Pretreatment

�Feed Composition

�Recovery Required for Feasibility

�Concentrate Treatment/Disposal

Once-Through

Permeate

RetentateFeed

Time Time

Permeate FluxSolute Concentration

P

F

R

Advantages

* Simple

* High Flux

* Low Solute Passage

* Short Residence Time

Disadvantages

* Concentration factor limited

No fouling

Fouling

Batch Recycle

Time

Advantages

• High Flux

• Low Solute Passage

• High Concentration

Factor

Disadvantages

• Long Residence Time

• Variation in retentate conc.

= non steady-state process

• High Energy Consumption

Permeate

Retentate

Feed

Time


P

R/F No fouling

Fouling


Feed-bleed operation

It is the most common method that

merges batch and single pass

operations.

The feed pump provides pressure,

while the recirculation pump

provides the tangential flow.

At the start-up, the feed pump is used to fill the recirculation loop,

after the recirculation pump is started.

When the desired concentration is reached in the recirculation loop,

the valve is opened and the feed flows into the loop at the same rate

as the permeate flow plus concentrate flow rate : FF = FR + FP

Permeate

Feed

Advantages

• Continuous operation

• Low residence time

• Low energy consumption

Disadvantages

• Complex

• Flux lower

• Higher solute passage

St 1Retentate

Time Time


P1

F

R2R1

P2

No fouling

Fouling

St 2

Multi-Stage Recycle


Standard

Pressure

RO

High

Pressure

RO

Permeate

Polishing

RO

Concentrate to further treatment

Permeate

Feed

High Recovery Membrane System


MEMBRANE MATERIALS

A survey on scientific

and patent literature

indicates that over 160

materials have been used

for membrane

manufacturing.

However, only a limited

number of polymeric and

ceramic materials have

reached commercial

status.

CHEMICAL RESISTANCE OF POLYMERIC

AND CERAMIC MEMBRANES

Comparison

between the

chemical

resistance of

polymeric and

ceramic

materials used

for membrane

production

Polymeric or Ceramic ?

� Polymeric

– Advantages

� wide range of polymers

� wide range of

modules/configurations

� widespread use

� low investment cost

– Disadvantages

� limited resistance to solvents,

oxidants, high temperature,

pH

� limited life

� Ceramic

– Advantages

� resistance to solvents,

oxidants, high temperature,

pH

� long life

– Disadvantages

� RO/NF not currently available

� high investment cost

MEMBRANE MODULES AND CONFIGURATIONS

Ceramic membranes :

- plate

- single tube

- multichannel monolith

- hollow-fibre (not well developed)

Polymeric membrane

- flat sheet

- single tube

- spiral-wound

- hollow-fibre

POLYMERIC MEMBRANE

(flat sheet)

Industrial-scale, flat-sheet

membrane module

POLYMERIC MEMBRANE

(tubular)

Scheme of a traditional tubular membrane module

POLYMERIC MEMBRANE

(spiral-wound)

CERAMIC MEMBRANE

(single tube and multichannel monolith)

SCHUMACHER (US)

ATECH (GER)

TAMI (FR)

EXEKIA-PALL (US)

FAIREY (UK)

Lenght: about 1200 mm

Outer diameter:

- single tube (up to about 25 mm)

- multichannel monolith (up to about 40

mm)

CERAMIC MEMBRANE

(multichannel monolith)

TAMI (FR)

122mm x 864 mm - 10,7 m 2

up to 99 elements – ca. 35 m 2

CERAMEM (US)

CERAMIC MEMBRANE

(hollow-fibre)

CEPAration – TNO (NL)

Material: Al2O3

Outer diameter: > 0,5 mm

Thickness: > 0,5 µm

Pore size: 0,1-1 µm

Porosity: 30-50 %

Membrane surface:

from 0,05 to 1 m2

�Tubular

�Spiral-wound

Surface area/Volume ≈ 101-102 (m2/m3)


�Hollow-fibre



30 µm30 µm

�Flat

Surface area/volume ratio of

different membrane modules

MEMBRANE MODULE CONFIGURATION

MEMBRANE MODULE CONFIGURATION

Membrane

geometry

Suspended

solids

tolerance

Control of

fouling

Cleaning

easiness

Packing

density

Cost per

volume

unit

Tubular Good Excellent Excellent Low -

Medium

Medium -

High

Spiral-

wound

Low Limited Medium High Low

Hollow-

fibre

(external

feed)

Scant

(Good)

Scant

(Good)

Scant

(Good)

Excellent High

(Low)

Flat Medium Good Medium Medium Medium -

Low

Advantages/disadvantages of different membrane modules

Geometries

GEOMETRIES

Tubular

Spirals

Hollow Fibre

Ceramics

RO NF UF MF

�Permeate Flux [L m-2 h-1]

Depends on driving force (ΔP - Δπ) T, Vr, µ,…

�Retention

FPM

t

RRR

ΔπPJ

++

−=

100C

CCR%

f

pf×

−=

MEMBRANE PERFORMANCE (flux-retention)

CF = feed solute concentration

CP = permeate solute concentration

�Permeate Flux [L m-2 h-1]

Parameters affect drivingforce (ΔP - Δπ) T, Vr, µ,…

FPM

t

RRR

ΔπPF

++

−=

RP = polarization layer resistanceRF = fouling resistance (pectine)

F = permeate flux

RM = intrinsic membrane resistance

∆P = transmembrane pressure differential (feed –

permeate)

∆π = osmotic pressure differential (feed –

permeate)

RESISTANCE MODEL FOR PREDICTING PERMEATE FLUX

A major limit in membrane

technology is represented by

“fouling”.

Fouling is a result of specific

interactions between the membrane

and various solutes that may cause:

A) pore narrowing/constriction

B) pore plugging

C) gel/cake layer formation

D) selective plugging of larger

pores

MEMBRANE FOULING

Time

Flux

w,0

w,f

wF

FFRR =

The amount of the membrane fouling can be obtained by

measuring pure water Flux before (F0,w) and after (Ff,w)

application

Fouling

�Types

– surface/macroscopic

– absorbed

– in-pore

�Effect

– flux decline (reversible/irreversible)

– separation change

Effect of Fouling

� Flux � Separation

Time Time

Retention

species < 0.1 µmFlux

100

0

- protein are strongly adsorbed on the surface of hydrophobic

membrane (e,g. polysulfone, polyethersulfone, polyvinilidene

fluoride)

- macromolecule-membrane

interactions tend to plug the

pores and form a layer on the

membrane surface that greatly

lowers the permeate flux

MEMBRANE FOULING

Surface of a fouled membrane

Control of Fouling� Crossflow - increase crossflow rate / Re

� decrease fouling

� increase energy consumption

� Pressure - increase pressure

� short term flux increase

� fouling increase?

� Pre-treatment - filter/pH alteration/chemical addition

� decrease fouling

� cost of pre-treatment

� Membrane Selection

� protein solutions >> hydrophilic

� non-aqueous >> hydrophobic

� Cleaning - periodic removal of foulant

Cleaning� Physical

– limitations

– methods

� Chemical

– aqueous

� water flush

� caustic/caustic

detergent

� enzyme detergent

� acid

� oxidants

– non-aqueous

� specific solvents

• Limitations

– pH tolerance

– temperature

– chemical attack

– solvent resistance

MEMBRANE CLEANING

Cleaning is the removal of foreign materials (foulants) from

the surface and body of the membrane, in order to restore

membrane performance.

Physical cleaning

- backwash

- foam balls

Chemical cleaning

- oxidants

- acid / caustic

- detergents

� Reverse Osmosis - Nanofiltration

� Demineralisation

� Industrial wastewater treatment (textile, fermentation,

pharmaceutical, etc.)

� Pharmaceutical industry

� Wine sector

� Whey from dairy farming

� Other sectors in the agro-industrial field

� Treatment of sugar solutions

� Concentration of organic solutions

� Treatment of well, surface and seawater

� Selective removal of metals from well and surface water

� Removal of soluble organic substances

� Removal of radioactive species from well and surface water

� Dumps percolates

Main applicationsWater

treatment

Biochemical

processes

Food

industry

Chemical,

pharmaceutical

industry

� Microfiltration/Ultrafiltration

� Fermentation broths

� Clarification of food liquids

� Electronic industry

� Wine sector

� Pharmaceutical industry

� Agro-industry

� Mechanical industry

� Chemical industry

� Clarification treatments

� Membrane bioreactors

Membrane Processes used in the various

sectors of the Food Industry

Production of fruit juices

and/or syrups

Cheese industry

Production of beer

Production of wine

and vinegar

Production of

proteins: from

albumen, eggs,

potatoes

Sugar industry

Vegetable oils

Biological processes

Starch industry and

its derivates

Jelly industry

MEMBRANE APPLICATION – DAIRY INDUSTRY

(milk micro and ultrafiltration)


(milk ultrafiltration)

The main benefits of

ultrafiltration are:

- increase (10-30%) in

yield of cheese

- decrease of the amount

of enzyme (rennet)

- volume reduction of

milk to handle

- little or no whey is

produced


(whey ultrafiltration)

Whey is a by-product of the cheese industry.

Whey is the liquid fraction that is drained from the curd during

cheese preparation.

Typically, every 100 kg of milk will

give about 10-20 kg of cheese and 80-

90 kg of liquid whey

Whey disposal is a major problem for

the dairy industry because of the very

high BOD (Biological Oxygen

Demand)

Component %

Total solids 6,3

Protein 0,6

Fat 0,1

Lactose 5,0

Ash 0,6

Water 93,7

Ultrafiltration of cheese whey to recover protein

The ultrafiltration

membrane separates

protein (retentate)

from salts and lactose

(permeate).

A whey protein

concentrate (WPC) is

the final product.


(whey ultrafiltration)

MEMBRANE APPLICATION – BEVERAGE INDUSTRY

(apple juice production)

Conventional

methodMembrane

process

MEMBRANE APPLICATION –BEVERAGE INDUSTRY

(fruit juice production)

Fruit juice is concentrated without

altering product quality

Tradizional process

Efficiency

80-94%

Process duration

12-36 hours

UF process

Efficiency

95-99%

Process duration

2-4 hours

ADVANTAGES

� A better retention of flavouring

compounds

�Lower contamination

�Lower thermal damnages to the

products

�Lower energy consumption

MEMBRANE APPLICATION – BEVERAGE INDUSTRY

(wine production)

The first UF step removes microorganisms and colloids

The MF step removes yeast

The second UF step is a final filter: it could also be a sterilizing microfilter

Advantages

•Product quality improvement (lycopene, colour, vitamin C, etc.)

•New products’ development

Juice concentration: 7-8 Bx

Discharge water

Tomato

juice RO

Forward osmosis

Reformulation

MF serum

Concentrate tomato juice

Tomato juice

MFDischarge water

RO

Concentrate

pulp

Concentrate

Integrated process

Application: fruit juice industryTomato juice production

SUGAR BEET

SLICES

DIFFUSION

WATER

PRESSED

WATERS

PRESSINGHUMID

PULP

RAW

JUICE

PRESSED

PULP

DEFECATION

FILTRATION

2° CARBONATATION

FILTRATION

1ST CARBONATATION ULTRAFILTRATION OR

MICROFILTRATION

LIGHT

JUICE

SWEETENING WITH

ION-EXCHANGE

RESINSEVAPORATION

JUICE

THICKCRISTALLIZATION

SUGAR

MOLASSES

CaO

CO2

CO2

Sugar industry

Substitution of clarification processes with membrane processes

Advantages:

�Reduction of employed raw materials and

instrumentation.

�Energy consumption reduction.

�Environmental impact reduction.

�Sugar quality improvement.

Activities to develop in close cooperation with productive structures:

� Line 1) Filtration and clarification of extra-virgin oil, direclty at the mill or before the bottling process.

� Line 2) Treatment of vegetation waters, aimed at the recovery and valorisation of noble products (poliphenols and others) to obtain a purified water that can be recycled both for agricultural purposes and for olive washing before pression, or can be discharged.

� Line 3) High-quality de-hydrated aromatic herbs production for human consumption, obtained through forward osmosis. The process is being applied to basil leaves.

� Line 4) Study for the set-up of an integrated ecosustainable process for the production of pickled olives. The process is being applied to the production of Taggia olives (salt solution management).

Results from a project with “Consorzio Ligure dei

Prodotti Tipici Fiori e Frutta di Imperia”, concerning

four different lines:

Schema del processo di produzione dell’olio vergine di oliva con le indicazioni dei punti in cui s’intende svolgere le attività di ricerca oggetto del presente progetto.

Olives

Olive paste

Vegetationwater

Oil

Residues

Washing

Crushing

Kneading

Settling

Membrane filtration(clarification and stabilization)

Water recovery and recycle

Line 1

Line 2

Storage

Water

Recovered

water

Introduction of membrane processes in oil

production

Clarification of extra-virgin oil

Approach: physical innovative process aimed at product quality improvement and

quality level preservation in time.

INTRODUCTION OF MEMBRANE FILTRATION PROCESSES

Membrane filtration processes can be applied to oil production. The

resulting oil will be:

� purified

� brilliant

� with better organoleptic qualities

Extra-virgin oil as it is Filtered extra-virgin oil

Results of microfiltration tests performed on extra-virgin

oil at Isnardi manufacturing plant.

Clarification of extra-virgin oil

OlivesWashing

Olive paste

Pressing

KneadingCrushing

OilVegetation waters

Membrane processes

residue

Olive oil production cycle

Treatment of vegetation water

Vegetation waters

Olive washing water

Vegetation water

Added centrifugation water

Filter disc washing water

Instrumentation washing water

Elements Amount (%)

83,2

1,8

Water

Inorganic elements

Organic elements

1,0

2,0

7,5

1,5

1,5

1,5

Lipids

Nitrogenous compounds

Sugars

Inorganic acids

Polyalcohol

Pentoses, Tannins

Glycosides traces

5,5

15000 - 110000 (mg/l)

pH

BOD5

COD 20000 - 150000 (mg/l)

Surface waters Public sewage

CODMax 40 500

BOD5 Max 160 250

Legal restrictions for industrial

discharges (d.lgs.11 maggio 1999, n°152)

Treatment of vegetation waters

Present disposal processes for vegetation waters

�Lagooning processes

�Methanogenic microrganisms

�Drying processes

�Fertilization (Spreading)

�Discharge

�Incineration

�Dilution

Practical and environmental problems

Impossibility to use metabolic products

Lack of stability, hygroscopicity

Possibility of euthophication

Ground water pollution

Costly process


Identified processes

Vegetation

waters

Microfiltrazione

• Irrigation Water

•

Microfiltrazione

•

• Reuse for olive washing

Recovery of concentrate

to be valorised

Integrated process optimized on lab-scale at the Department

of Chemistry and Industrial Chemistry, aimed at the

valorisation and treatment of vegetation waters.


Pilot plants employed for test at Frantoio Isnardi

Pilot plants (Microfiltration and Reverse Osmosis) set up at the

Isnardi oil mill for for tests


30 litri concentrato MF 25 litri concentrato OI 945 litri permeato OI Qualitative and quantitative assessment

Integrated process: resultsTreatment of Vegetation Waters

30 l of MF concentrate 25 l of OI concentrate 945 l of OI concentrate

Example of innovative process of treatment and recycling of vegetation water

Project carried out on behalf of the Consorzio Ligure dei Prodotti Tipici Fiori e Frutta - Imperia –

Vegetation water

Microfiltration

Reverse Osmosis

•Irrigation Water •Reuse for olive washing

Recovery of concentrate to be treated

Membranes

�Act as a total barrier against unwanted substances

�Carry out separations at molecular level

�Allow purification and recycling of polluted water

�Allow to water destined to human consumption from

any kind of raw water

�Allow obtaining water with the desired quality

• Membrane processes are a very innovativenanotechnology, used to obtain high-quality water.

• Because of their characteristics and for the high

technological levels reached, they have become the keyto sustainable development.

MEMBRANE PROCESSES: INNOVATIVE TECHNOLOGIES

FOR THE RECOVER OF WASTEWATER.

Water, despite being a renewable resource, is today a limited resource

- The consumption rate is faster than the recovery rate (rain) - The quantity of polluted water is higher than primary water

Depurazione o

Usi industriali

Depurazione

Agricultural useEnvironment

Drinking water treatment

Municipal useIndustrial use

Usi industriali

Wastewater treatment

Water treatment

Current cycle of water usage

� Worldwide � High income

countries

8%

82%

10%

Municipal AgriculturalIndustrial

� Low income

countries

Worldwide use distributionSource: World Bank

8%

70%

22%

Municipal uses Agricultural usesIndustrial uses

30%59%

Municipal Agricultural

Industrial

Access to drinking water:

Access in less than 15 minutes walk to at least 20 l/day of usable water

Worldwide population: about 6 billion

Population with no access to drinking water: about 1.5 billion

General Observations

The problem of having access to water quantities sufficient for all uses – drinking, industrial, agricultural – is a worldwide problem.

Generally speaking water is not lacking, what is missing is its equal distribution in places, times and in the quality needed.

About 80% of water resources is destined for agriculturalirrigation, while water demand is constantly increasing,particularly in urban areas. Since, according to FAO, there are nonew water sources, it is crucial to spare the existing ones and usealternative sources like brackish water-bearing strata, drainagewater and seawater, as well as treated wastewater.

This problem can be solved with various approaches:desalination, transportation, reuse.

Desalination processes can be divided in two typologies:

Thermal treatments

- Flash multistadium distillation

- Multiple effect distillation

- Evaporation with steam compression

Membrane treatments

- elettrodialysis (ED)

- Reverse osmosis (OR)

DESALINATION PROCESSES

The selection of the desalination technology depends

on the feeding water quality.

REVERSE OSMOSIS

Applying a pressure difference on the membrane sides, a

concentrate (pickle) is obtained and a permeate (desalinated pure

water)

Ghalilah

Operative Pressure: 50-80

bar.

Main advantages

- simple construction

- possibility to implement the capacity of the system

- energy saving is higher then thermic processes

Drawbacks:

- product with higher salinity

- Membrane fouling.

KEY FACTOR

good quality of the feeding seawater

REVERSE OSMOSIS

PRE-TRETMENTS REVERSE OSMOSIS

In reverse osmosis systems, the main problem is the membrane

fouling.

Conventional pre-treatments are: clorination, coagulation, flotation,

filtering, antiscalants dosage, declorination and filtering on cartridge

PROBLEM:

They do not always allow to

obtain a good quality of

feeding water.

All desalination processes require pre-treatments. Each type of

desalination process require a different feeding seawater quality.

ULTRAFILTRATION as pre-treatment for the reverse osmosis

Main objectives:

�Optimising of the ultrafiltration process to have a constant

quality for the feeding water in reverse osmosis plant

� Reducing of solfate concentration in the seawater, allowing

higher temperatures in nanofiltration.

Study of membrane processes as pre-treatments indesalination processes

Hollow fiber

DEAD-END filtering

IN-OUT mode

PILOT PLANT (harbour of Genoa)

The plant is composed by two sections:

UF SECTION NF/RO SECTION

NANOFILTRATION

UF: OBTAINED RESULTS

The permeate quality is strictly influenced by the surface

characteristics membrane.

It is important to optimise the preparation process and the

selection of the material.

The A membrane, made of PESM, showed better

performances

The treated seawater reached a goos quality in terms of

fouling.

SEZIONE UF: CONCLUSIONS

�Treatments lyne are shorter, so it means a lower surface need

� the chemical agents consumption is lower� Fouling velocity decrease, so less frequent washing operations

� membrane life for RO becomes longer

� The permeate flux for RO membrane can be increased

� a better quality of desalinisated water

� desalination process is more convenient

The hybrid process UF + RO has more advantages in

comparison to the system «traditional pre-treatments»

+RO:

Water reuse by means of innovative and low cost technologies has

become a worldwide need for the management and preservation of

water resources

MEMBRANE APPLICATION

(waste water treatment – water recovery)

Advantages of membrane technology compared with conventional treatments

• Steady quality of permeate independently of raw water quality

• Low SDI of the permeate

• Reliable removal of bacteria and viruses

• Plants are highly automated

• Plants are very flexible in their performance

• High reliability of operation

• Chemicals free operation

Membrane processes as an alternative to traditional technologies for drinking water

Drinking water treatment

Acqua Grezza

Coagulation

e Flottazione

Filtrazione

Clorazione

Raw water

Coagulation

Flotation

Clarification

Filtration

Chlorination

Membrane processes

Drinking water

Lower chlorine consumption

Specific applications in areas of water shortage

� Water reclamation from civil drains:

– For civil use (services, irrigation etc.)

� Water remediation

Wastewater

Waste

Water to the consumer

Treatment(Chemical-physical)

Hygienic stabilization

Activated sludge process

ClarificationMF/UF

N F / O I

Water from the Elbe river, Germany

Aim of the process:To produce 350 000 m³/dof treated water (Elbe).

Process:Combination (UF) and (RO)

Economy:Amortization of UF-RO plant costs in 2.6 yearsTotal cost 0.70 €/m³

Example of innovative process of wastewater recovery and recycling from an industrial laundry

Traditional process

Innovative process

laundry

5 mc/h

A1: 5 mc/h

detergent; hypoclorite 3 mc/h

P1: 3 mc/h

detergent; H2O2 3 mc/h

L1: 3 mc/h

acetic acid; H2O2

R1: 6 mc/h

drinking water11 mc/h

5 mc/h

PR1: 5 mc/hPRESS

SOAK

PRE-WASH

WASH

RINSE

3

PRE-TRE 13 M.F. 10 R.O. 7

3 tap water

water to be treated Y

to the rinse

to the wash

Membrane processes as an alternative to

traditional technologies for drinking and

wastewater treatment

Tertiary treatments

Wastewater

Screening

Primary sedimentation

Biological treatment

Secondary

sedimentation

Membrane bioreactor

Drain or reuse

Wastewater treatment

Development a new of modules with a high surface/volume ratio at ever decreasing costs

Costs reduction in time

10

100

1.000

10.000

100 1000 10000 100000 1000000

Cumulative membrane sale in m2

Co

st

in $

pe

r 1

00

mc/g

1989

1996

1992

1995

1990

1998

Zenon

Memcor-USFilter

KMS

Can treat 1000 m3/day

Permeate

Air

with reversible

backflushing

fouling

Drain

Feed

Concentrate

Deposit formation Removal of the

deposited layer

Filtration and backwashingPermeability

[l/(m2

·h·bar)]

TIME

TMP limit

Mimimum flux

backwashing Filtration

interval

Flux recovery

with backwashing

Chemical wash with frequency from 3 to 6 months

depends on• water initial characteristics

• TMP• backwashing procedures

a

Flux decrease without backwashing

Chemical wash

Acceptable flux line

Developing the technology define the new working modalityto control flux stability in time (Fouling)

Worldwide membrane market

UF

25%

MF

25%

RO

50%

- Desalination

- Ultrapure water

- RO pre-treatment

- Drinking water

- Food industry

- Drinking water

- Water treatment

Sale

s (

MLD

€)

Year

*

0

1

2

3

4

5

6

7

8

9

2004 2005 2006 2007 2010

forecast

Year

Ma

rke

t (M

LD

US

D)

0

50

100

150

200

250

300

350

400

2005 2010

Europe

World

Approx 1000 new MBRs will be built in the next 5 years

Membrane bioreactorsMembrane treatmentsOther advanced treatments

Average annual growing rate

10.9%8-9%5.5%

MBR - Market

T. Melin, Desalination 187 (2006) 271

Area Dimention(m3 /d )

Membranesupplier

Start up year

Rödingen, DE 2.400 Zenon 1999

Ile de Yeu, FR 2.260 Zenon 2000

Markrantstädt, DE 3.600 Zenon 2000

Swanage, UK 12.720 Kubota 2000

Campbeltown, UK 2.678 Zenon 2001

Westbury, UK 3.536 Kubota 2002

Lowestoft, UK 14.160 Zenon 2002

Brescia, IT 42.000 Zenon 2002

Monheim, DE 2.400 Zenon 2003

Schilde, BE 6.520 Zenon 2003

Kaarst, DE 45.144 Zenon 2003

Waldmössingen, De 2.160 Zenon 2004

Guilvinec, FR 2.600 Kubota 2004

La Bisbal, SP 3.240 Zenon 2004

Riells I Viabrea, SP 5.160 Kubota 2004

Uerikon, CH 5.200 Zenon 2004

Cardigan, UK 8.640 Kubota 2004

Buxton, UK 10.627 Zenon 2004

Varsseveld, NL 18.120 Zenon 2004

•Zenon environmental

•Kubota

•Ionics/Mitsubishi Rayon

•USFilter

•Aqua-Aerobics/Pall

•Norit X-flow

MBR – European plants

Innovative processes and technologies for wastewater treatment by MBR = Membrane Biological Reactor

A MBR combines a biological process with a membrane separation

process (generally a MF or UF).

In practice the membrane substitutes the secondary sedimentation and

optimizes the biological purification process.

Air

Sludge drain

PermeatoPermeateWastewater

Air

Sludge drain

Permeate

Wastewater

Retentate recycling

Immerse membrane bioreactor External circulation membrane

bioreactor

Treatment of domestic wastewater with MBR

Wastewater

Pre-treatment Primary sedimentator

Membrane filtration

Final effluent

Sludges drying process / disposal

Active sludges

Agricultural use

Nanofiltration

Reverse Osmosis

Industrial use

Drain (sensitive areas)

Wastewater

Pre-treatmentPrimary sedimentation

tank/settler Active sludges

Biomass

stabilization

Sludges drying process / disposal

Secondary sedimentation

tank

Sand filter

Disinfection

Final

effluent

Drain

TR

AD

ITIO

NA

LM

BR

Active sludges conventional

treatment plants show the

following disadvantages:

•Large bulk

•Low depuration efficiency

•Low quality waste (SS, bacterial

load, high nutrients

concentration, etc.) therefore

can only be used at high costs

•Low flexibility

•High sludge production

Operating conditions of MBR treatment plantsTypical MBR immersed membrane operating conditions

Parameter ValueFlux

- Instant L/(m2h) 25-35- Long term L/(m2h) 15-30

Transmembrane pressure kPa 20

Biomass concentration gMLSS/L5-25

Solids retention time (STR) days>20

Sludges production kgSS/(kgCODday) <0.25Hydraulics retention time (HTR) hours 1-9Feed/microorganism ratio kg COD/(kg MLSSday) <0.2Volume (kgCOD/m3 day) Up to 20Air capacity Nm 3 /h per module 8-12Temperature °C 10-35pH 7-7.5Backwash frequency min 5-16Backwash length s

15-30Filtration energy consumption kWh3/m 0.2-0.4- For membrane aeration % 80-90- For permeate pumping %

10-20

The suggested biomass concentration is 12-15 g/L

T. Melin, Desalination 187 (2006) 271

Treatment of industrial wastewater with MBR

Oil contaminated industrial wastewater has been successfully treated

using a submerged membrane reactor. Removal efficiency is 98%

Lab-scale MBR

Hollow fibre membranes

Hydrocarbon removal

Removal efficiency % (COD - BOD5 - SST)

40,0

60,0

80,0

100,0

24-lug 26-lug 28-lug 30-lug 01-ago 03-ago

Days

%

COD BOD SST

80 %

Days COD

removal

efficiency

%

BOD5

removal

efficiency

%

TSS

removal

efficiency

%

24-lug 98,2 98,3 100

26-lug 93,6 93,9 100

28-lug 88,6 89,2 100

31-lug 94,0 94,4 100

02-ago 96,1 96,3 100

04-ago 96,1 96,3 100

Treatment of civil wastewater using MBRs carried out by the University of Genoa (example 2)

The removal of micro-organism

and TSS is complete

Employed membranes:

hollow fibers produced by

KMS Coreana

Material HD

Poliethylene

Porosity Symmetrical

Thickening 400 µm

Nominal

diameter of

pores

0,4 µm

Filtering

surface

40 m2

MBR pilot plant in Genoa-

Voltri (example 3)

Boro (mg/l)

0,14-0,4

0,15 Cianuro tot.(mg/l)

0,04-0,05

0.02

pH 6,5-7,5

6,5-7,5

Cadmio (mg/l)

Ass. Ass. Solfuri (mg/l)

Ass. Ass.

S. Sospesi T.(mg/l)

440 3-4,5 Cromo Tot (mg/l)

Ass. Ass. Solfiti (mg/l)

0,5-3,75

0.5

BOD5 (mg/l)

300 10-15 Cromo VI (mg/l)

Ass. Ass. Solfati (mg/l)

34-97

50

COD (mg/l)

400 20-30 Ferro (mg/l)

0,05-0,15

0.05 Cloruri (mg/l)

26-130

60

Fosforo Tot. (mg/l)

7 2 Manganese (mg/l)

0,01-0,3

0.02 Floruri (mg/l)

0-0,05

0.02

Azoto Totale (mg/l)

40 15-40 Mercurio (mg/l)

Ass. Ass. Solventi cloruri t.

Ass. Ass.

Azoto Amm. (mg/l)

40 0 Nichel (mg/l)

0-0,03

0.06 Solv. Org. Arom.

Ass. Ass.

Conducibilità (µS/cm)

3000 < 3000

Piombo (mg/l)

Ass. Ass. Mat. Grossolani

Ass. Ass.

Alluminio (mg/l)

0-0.4 0,05 Rame (mg/l)

0-0,05

0,01 Fenoli (mg/l)

Ass.

Risultati

Valori in ingresso

Valori in uscita

Riuso

Tutti i valori in uscita sono inferiori ai Limiti di

legge per il riuso D.M.12 giugno 2003, n.185

Impianto pilota MBR

di Genova-Voltri

Average inlet: COD: about 400 mg/lBOD: about 300 mg/l

Results: COD - BOD

The Microorganisms and TSS removal is complete

MBR pilot plant in

Genoa-Voltri

Industrial wastewater containing hydrocarbons

Industrial wastewater contaminated with oil have been successfully

treated using a MBR. The removal efficiency has been 98%.

MBR at laboratory scale

Hollow fibers membrane

Hydrocarbons removal

Collecting gas (400 °C)

Gas cooling (17°C)

Elimination NH3

Elimination H2S

Utilities

Ammoniawater Decantation

Process water

Tar

Stripping

Biologic

NH3

Gas treatment

Design parameters

To design the new structure has been referred tothe plant condition:

• Feed : 36 m3h-1 (864 m3d-1)• Recirculation: 576 m3h-1

• COD= 2600 mg l-1

• Ntot= 270 mg l-1

• N-NH3=110 mg l-1

Study objectiv

Assess the feasibility of revamping of the system that involves the insertion of denitrification and microfiltration with the reuse of existing structures

Objectiv for the parameter of the descharge waterThe new plant have to produce water that respect thelimits for discharge into rivers

1-3

1-tot

-1

l mg 15 NH-N

l mg 20 N

l mg 160 COD

≤

≤

≤

MBR for the treatment of industrial wastewater- They allow the preservation of slow growing microorganisms able to degrade

complex organic matter (soluble and particulate).

- Flexible and optimal STR control (from <1- >30 days) and independent from

HRT, allowing an optimal control in microorganisms populations.

- Compact bioreactor

- No biodegradable compounds tend to remain more in the sludge

- Short start-up

- No need of adjuvants for settling

- Revamping of existing activated sludge treatment plants

- Direct application of inverse osmosis for the reuse.

The colloidal and suspended fraction is responsible for fouling.

Its concentration and composition depends on biological parameters and

membrane cut-off.

Tight correlation between operative parameters and membrane fouling:

-Choice of the most suitable membrane (material and geometry)

-Critical flux determination

-Choice of appropriate operating conditions

-Flux and wash optimization

The success of membrane processes is based on fouling control (MBR)

Membrane bioreactors

ADVANTAGES

� High efficiency (BOD and TOC removal between 96-98%) high nitrification and total denitrification with the denitro stage

� SS absence, absence or little presence of bacterial charge in the permeate

� Direct use of clarification which can be qualified at low cost for any kind of use

� High flexibility with respects to the charge, complete automation and plant control

� Reduction in dimensions and installation costs (without the sedimentation stage)

� Low costs when comparing not only the mc/H treated but also the values obtained of treated water

DISADVANTAGES

� Technologies still fairly unknown (high initial mistrust)

� Need to train technicians with high competence and engineering knowledge as well as experience on membrane and membrane processes (for this purpose the University of Genoa is currently running a second level University Master)

•Present technologies allow a virtually total reclamation.

•Reuse can be complete; Italian law limit water reuse to the fields of agriculture

and industry.

Domestic use

Environment

Industrial use and irrigation

Usi industriali

Purification or Potabilisation

Purification

Present purification technologies

Allow to bring

wastewater back to

the required

characteristics

Water recycling and reuse: general aspects

Primary water

Reuse resource

Wastewater

TREATMENT PLANT

SITUATION AND DEMAND

Plain of Albenga

� The creation of a purification plant in Villanova is a keystone for the integrated management of water in the area of Albenga.

� A significant part of water destined to industrial, agricultural and human consumption is brought back to the natural cycle from the purification plant.

� It is assumed that the purification unit will produce and release re-usable waters for agriculture and industry. In any case, reclaimed water is brought back to itrs original characteristics and can be re-introduced into the environment.

� The area considered for water reuse includes 6 municipalities: Alberga, Ceriale, Garlenda, Ortovero, Villanova d’Albenga, Cisano sul Neva.

� The area in which the purification plant is situated is particularly interesting; for many reasons, it provides also a critical model for situations at the limit of permanent stress.

I fabbisogni

Study results:1) Need to create a purification plant aimed at the reclamation

and recycling of waters for a sustainable development of

agriculture in the plain of Albenga.

2) Need to have a high-quality water as a result of the

purification process (choice of a MBR plant).

3) Need to perform a treatment to reclaim 70 % of waters for

agruicultural use (choice of a NF/RO plant).

4) Importance and necessity for the area to take into account a

treatment plant on behalf of a third party (vegetation waters)

with zero discharge. Integrated membrane plant to treat at

least 20 mc/day.

The reclaimed water can be used for:

AGRICULTURE

RETURN TO HYDROGEOLOGICAL BALANCE

SALT-WEDGE REDUCTION

DESERTIFICATION PROCESS CONTROL

Membrane processes, alone or combined

with MBR, allow the use of water from

non-conventional sources, such as:

Urban wastewater

Primary waters lacking required

parameters

Hard and brackish waters

Present technologies allow to obtain water from non-

conventional sources

Conclusions

The introduction of membrane processes in thewater purification, reclycling and productionfields is widely spreading.

It is expected that, between 2015 and 2030, theoverall growth of water “production” throughthe treatment and reclamation of wastewaterwill be of 43%.

Conclusions

Global water market amounts to 224 MLD €, with an expected growth of 16-20 %.

presentazione Capannelli 21 10 2016.ppt [modalità ... · Nella distillazione a membrana il ruolo...

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Transcript of presentazione Capannelli 21 10 2016.ppt [modalità ... · Nella distillazione a membrana il ruolo...